1. Field of the Invention
This invention relates generally to flight vehicles and, more particularly, to vehicles which are joined and separable during flight.
2. Description of the Related Art
There are many different vehicles available for spaceflight. Some vehicles are unmanned, and do not involve carrying occupants. Examples of unmanned vehicles for spaceflight include space probes and satellites. Other vehicles are manned, and do include carrying an occupant, such as a human. Examples of manned vehicles are disclosed in U.S. Pat. Nos. D302,148, 3,369,771, 3,700,193, 3,702,688, 3,866,863, 4,265,416, 4,452,412, 4,802,639, 4,901,949 5,564,653 and 6,612,522, the contents of which are incorporated by reference as though fully set forth herein. U.S. Pat. No. 6,612,522 provides an extensive discussion about the background and history of spaceflight.
Vehicles for manned spaceflight typically include a launch vehicle, having a launch propulsion system, and a crew vehicle or orbiter carried by the launch vehicle. The launch propulsion system propels the crew vehicle into orbit. The crew vehicle includes a crew cabin and return propulsion system. The crew cabin houses a human occupant, and the return propulsion system returns the crew vehicle from orbit. The crew vehicle can be of many different types, such as a space capsule and space shuttle.
In some manned vehicles, the launch propulsion system launches the crew vehicle vertically from a launch pad. Examples of such vertical launch propulsion systems include a rocket. In some instances, the rocket is retrieved after launch so that it can be reused to reduce costs and waste. An example of a vertical launch system is disclosed in U.S. Pat. No. 3,866,863. It should be noted that the rocket provides propulsion, but it typically does not provide much lift because it does not include wings. The rocket may include fins for stabilization. However, any lift provided by the fins is negligible.
The crew vehicle of a vertical launch system generally provides more drag than lift during launch. However, some crew vehicles may provide lift after separation from the launch propulsion system. For example, the space shuttle includes wings that provide lift, which only allows it to controllably glide and land but do not add lift on ascent.
In other manned vehicles, the launch vehicle is an airplane, which allows the crew vehicle to be horizontally launched from a runway. The airplane carries the crew vehicle to a predetermined altitude at which separation occurs, and the crew vehicle propels itself into orbit. The airplane is landed after launch so that it can be reused to reduce costs and waste. Further, the crew vehicle includes wings that provide lift, which allows it to controllably glide and land using its return propulsion system. Examples of horizontal launch systems are disclosed in U.S. Pat. Nos. 4,265,416, 4,802,639 and 4,901,949.
Although the disclosed systems for manned spaceflight may be suitable for their intended purposes, it is desirable to provide a system which reduces the costs of space flight.